Adjustable mounting for suspension strut

ABSTRACT

An adjustable mount for the upper end of a motor vehicle suspension strut located in a bush (12) wherein a flange (22) is located between a clamping plate (13) and a face plate (14) with studs (17) passing from the clamping plate through enlarged apertures (15) in the flange (22), holes (16) in the face plate (14) and aligned holes (18) in the top of the vehicle chassis suspension tower (11), and being secured by nuts (19). Before the nuts (19) are tightened, the flange (22) may be moved in a sliding fashion between the clamping plate (13) and face plate (14) to locate the bush (12) and upper end of the strut into the desired location for correct castor and camber settings. Reference is also made to the provision of screwdriver slots (25) to permit the flange (22) to be levered into the desired location using a screwdriver when the suspension is under load.

This invention relates to adjustable automotive suspension componentsand has been devised as an adjustable mount for the upper end of avehicle suspension strut, particularly although not limited to a mountfor the upper ends of McPherson-type struts used in the front suspensionof motor vehicles.

BACKGROUND ART

Strut-type suspension is well known in motor vehicles wherein atelescopic strut normally incorporating an hydraulic damper is used asone locating member for a motor vehicle wheel. The most common form ofstrut suspension is the so-called McPherson strut where the suspensionspring is located concentrically around the telescopic strut which hasan upper mounting point to the vehicle chassis in a tower located abovethe front wheel arch and protruding into the engine bay of the motorvehicle. The lower end of the strut is typically further located by atransverse link and a fore and aft or drag link.

The wheel alignment of a motor vehicle, and particularly the front wheelalignment is important to the safe handling of the vehicle and topreventing wear on the tires. There are many times in the life of avehicle when it is necessary or desirable to adjust the castor andcamber of a motor vehicle wheel either due to normal wear and tear or tosome form of minor damage such as the striking of kerbs or otherobstacles. On many motor vehicles fitted with McPherson strutsuspensions, this adjustment is often difficult to perform as the motorvehicle manufacturer provides little or no mechanism for relocating theupper end of the strut where it mounts into the vehicle chassis. It isoften necessary to relocate the mounting point of the upper end of thestrut to achieve the desired castor and camber settings.

It is common for the upper end of a McPherson strut to be secured to thechassis member by way of three vertical studs located on a pitch circleand passing from a flange at the upper end of the strut through alignedholes in the vehicle chassis member. Some manufacturers have provided adegree of adjustment by locating the axis of the strut off-center fromthe pitch circle of the studs so that disengaging the studs from theholes in the vehicle chassis member, rotating the strut and re-engagingthe studs through the holes will relocate the axis of the strut relativeto the vehicle chassis member. This is however an extremely coarseadjustment which only permits the top end of the strut to be located inthree defined positions. Furthermore, if it is required to alter thecamber of the suspension without affecting the castor (or visa versa),this adjustment is not possible using the mounting described above.

DISCLOSURE OF THE INVENTION

The present invention therefore provides an adjustable mount for theupper end of a vehicle suspension strut allowing the strut to berelocated relative to a vehicle chassis member, said mount comprising abush adapted to receive and secure the upper end of the strut, a flangeextending radially outwardly from an upper part of the bush and havingupper and lower faces, a clamping plate adapted to abut the lower faceof the flange and having an opening therethrough larger than theperimeter of the bush such that the clamping plate can slide over thelower face of the flange over a limited area, and a plurality of studsextending upwardly from the clamping plate through apertures in theflange, each said aperture being significantly larger than the diameterof the stud passing therethrough in directions both radial andcircumferential to the axis of the strut, permitting sliding movement ofthe flange relative to the clamping plate.

Preferably the apertures are at least twice as large as the diameter ofthe studs in directions both radial and circumferential to the axis ofthe strut.

Preferably a face plate is provided abutting the upper face of theflange, said studs passing through aligned holes in the face plate.

Preferably the flange is provided with slots orientatedcircumferentially relative to the bush, said slots being sized toreceive the end of a screwdriver blade and being located such that ascrewdriver engaged with a selected one the slots when the mount isinstalled in a vehicle can be used as a lever bearing against an edge ofthe vehicle chassis member to lever the flange and bush into a desiredposition relative to the clamping plate and vehicle chassis member.

BRIEF DESCRIPTION OF DRAWINGS

Notwithstanding any other forms that may fall within its scope, onepreferred form of the invention will now be described by way of exampleonly with reference to the accompanying drawings in which:

FIG. 1 is an exploded perspective view of an adjustable mount for theupper end of a vehicle suspension strut according to the invention;

FIG. 2 is a cross-sectional elevation through the adjustable mount shownin FIG. 1, located in place in a vehicle chassis member;

FIG. 3 is a diagrammatic plan view of the top of a strut suspensiontower in a motor vehicle showing parts of the adjustable mount in place;

FIG. 4 is a perspective view of a prior art mount for the upper end of avehicle suspension strut; and

FIG. 5 is a cross-sectional elevation of the prior art mount shown inFIG. 4, in place in a motor vehicle.

MODES FOR CARRYING OUT THE INVENTION

The upper end of a telescopic strut suspension member of a motor vehicleis typically secured to a chassis member (11) which may be the top of apressed metal "tower" having a hole through the center of the toweraligned with the axis of the strut. The mount for the upper end of thestrut typically comprises a circular flange (1) (FIG. 4) from whichprotrude a plurality of equispaced studs (2) and in which is mounted anelastomeric bush (3) having an outer casing as part of the flange (1)and an inner casing (4). The upper end of the strut (6) is secured inthe inner casing (4) by way of a bearing (9) held in place by a nut (8)engaged with a thread (7) on the upper end of the strut.

Typically the strut incorporates a coaxial helical spring (10) throughwhich the weight of the motor vehicle is taken on the elastomeric bush(3).

The mount is secured to a chassis member (11) by passing the studs (2)through aligned holes in the chassis member and securing them in placewith nuts (5).

In the adjustable suspension mount according to the invention the mountshown in FIG. 4 is replaced by an adjustable mount shown in FIGS. 1, 2and 3 which permits the location of the upper end of the strut to bevaried relative to the vehicle chassis member (11).

The adjustable mount according to the invention comprises an elastomericbush (12) similar to the bush of the prior art mount having a flange(22) extending radially outwardly from the upper part of the bush (12).

The mount is provided with a clamping plate (13) adapted to abut thelower face of the flange (22) and having an opening (23) therethroughlarger than the perimeter of the bush (12) (in the vicinity of theclamping plate) so that the clamping plate can slide over the lower faceof the flange (22) over a limited area. The clamping plate is furtherprovided with threaded studs (17) extending upwardly from the clampingplate and preferably equispaced on a pitch circle. The studs passthrough apertures (15) in the flange (22), each aperture beingsignificantly larger than the diameter of each stud in both radial andcircumferential dimensions relative to the axis of the strut. To allow areasonable amount of adjustment, the apertures should be at least twiceas large as the diameter of the studs in directions both radial andcircumferential to the axis of the strut. The apertures (15) may be anydesired shape, eg: circular but in the preferred form of the inventionare approximately square or rectangular in shape with rounded corners ascan be clearly seen in FIG. 3.

Although it is not essential to the invention, in the preferred form thestuds then pass through aligned holes (16) in a face plate (14) which isfree to slide over the upper surface of the flange (22) so that theflange is loosely sandwiched between the upper face of the clampingplate (13) and the lower face of the face plate (14). In order to retainthe face plate and the clamping plate on the bush and flange, retainingmeans may be provided to loosely secure the face plate to the studs. Theretaining means may take any suitable form but typically compriseknurling or otherwise deforming the threads of the studs as shown at 26immediately above the location of the face plate once the clamping plateand face plate have been assembled on the flange (22).

The adjustable mount is assembled into the motor vehicle by passing thestuds (17) through aligned mounting holes (18) in the vehicle chassismember (11) and securing the mount to the chassis member by engagingnuts (19) ,(preferably over split washers (24) ) with the upper ends ofthe studs (17).

With the nuts (19) loosely engaged on the studs (17), the flange (22)and hence the mounting bush (12) is free to slide between the face plate(14) and the clamping plate (13) in any desired direction governed bythe size and shape of the apertures (15) in the flange (22). It istherefore possible to position the upper end of the strut in therequired location to achieve the desired castor and camber settingsbefore tightening the nuts (19) to secure the upper end of the strut inthat desired location.

To assist the movement of the flange (22) to the desired location, theflange may be provided with a plurality of slots (25) orientatedcircumferentially relative to the bush (12) and preferably located onconcentric pitched circles about the bush (12) as can be clearly seen inFIG. 3.

Each slot is sized to receive the end of a screwdriver blade so thatwhen the blade end is engaged in a selected slot (eg: slot 26) thescrewdriver may be used as a lever bearing against the adjacent edge(27) of the vehicle chassis member (11) to lever the flange and bushinto the desired position. Using this method it has been found that itis possible to relocate the flange and bush to a desired location evenwhen the weight of a vehicle with a heavy engine is fully upon the frontsuspension members. This is highly desirable as the geometry of thesuspension changes when the weight of the vehicle is removed from thesuspension and it is therefore far more accurate to adjust and locatethe suspension members when the weight of a vehicle is fully on thesuspension.

The procedure referred to above is performed while the nuts (19) areloosened, and when the flange (22) has been levered to the desiredposition for accurate wheel alignment, the nuts (19) are tightened to apredetermined torque setting to secure and locate the upper end of thestrut suspension.

By using this method of adjustment the axis (21) (FIG. 2) of the strutmay be positioned to any desired location within a predetermined area,eg: to a position offset from the center (20) of the pitch circle of theholes (18). The castor and camber settings may be independently adjustedon the motor vehicle by suitable front-to-back or side-to-side movementsof the upper end of the strut.

As a further preferred feature of the invention a reinforcing plate (notshown) may be interposed between the top of the chassis member (11) andthe underside of the nuts and washers (19,24). The reinforcing platetypically takes the form of a flat ring having holes therethroughaligned with the holes (18). The areas surrounding the stud holes in thereinforcing plate may be further reinforced with thick plate over theareas which overlap with the apertures (15) in the flange (22) so as toresist bending of the chassis member (11) in the vicinity of the holes(18) under the load imposed by tightening the nuts (19).

I claim:
 1. An adjustable mount for the upper end of a vehiclesuspension strut allowing the strut to be relocated relative to avehicle chassis member, said mount comprising a bush adapted to receiveand secure the upper end of the strut, a flange extending radiallyoutwardly from an upper part of the bush and having upper and lowerfaces, a clamping plate adapted to abut the lower face of the flange andhaving an opening therethrough larger than the perimeter of the bushsuch that the clamping plate can slide over the lower face of the flangeover a limited area, and a plurality of studs extending upwardly fromthe clamping plate through apertures in the flange, each said aperturebeing at least twice as large as the diameter of the stud passingtherethrough in directions both radial and circumferential to the axisof the strut, permitting sliding movement of the flange relative to theclamping plate.
 2. An adjustable mount as claimed in claim 1 wherein theclamping plate comprises a ring and wherein the studs are locatedequidistantly around the ring, aligned to engage with correspondingmounting holes in the vehicle chassis member.
 3. An adjustable mount asclaimed in claim 1 wherein a face plate is provided abutting the upperface of the flange, said studs passing through aligned holes in the faceplate.
 4. An adjustable mount as claimed in claim 3 wherein retainingmeans are provided to loosely secure the face plate to the studspermitting the flange to slide freely between the clamping plate and theface plate.
 5. An adjustable mount as claimed in claim 1 wherein theflange is provided with slots orientated circumferentially relative tothe bush, said slots being sized to receive the end of a screwdriverblade and being located such that a screwdriver engaged with a selectedone of the slots when the mount is installed in a vehicle by engagingthe studs through aligned holes in the vehicle chassis member can beused as a lever bearing against an edge of the vehicle chassis member tolever the flange and bush into a desired position relative to theclamping plate and vehicle chassis member.
 6. An adjustable mount asclaimed in claim 5 wherein the slots are located on at least one pitchcircle concentric with the bush.
 7. An adjustable mount as claimed inclaim 6 wherein two rows of slots are provided located on concentricpitch circles.